Mucilaginous, consisting of mucilage.Tenacious, adhering closely.
Mucilaginous, consisting of mucilage.
Tenacious, adhering closely.
What is the character of Gum?
Gum is capable of being dissolved in water, and forming with it a viscid transparent fluid; but not in vinous spirits or oil; it burns in the fire to a black coal, without melting or catching fire; and does not dissolve in water at boiling heat. The name ofgumhas been inaccurately given to several species of gum-resins, which consist of resin and various other substances, flowing from many kinds of trees, and becoming hard by exposure to the air. These are soluble in dilute alcohol. Gum is originally a milky liquor, having a greater quantity of water mixed with its oily parts, and for that reason it dissolves in either water or oil. Another sort is not oily, and therefore dissolves in water only, as gum Arabic, the gum of the cherry-tree, &c.
Viscid, thick, ropy.Vinous, having the qualities of wine.
Viscid, thick, ropy.
Vinous, having the qualities of wine.
Are the last-mentioned sorts properly called Gums?
No, though commonly called gums, they are only dried mucilages, which were nothing else than the mucilaginous lymph issuing from the vessels of the tree, in the same manner as it does from mallows, comfrey, and even from the cucumber; the vessels of which being cut across, yield a lymph which is plainly mucilaginous, and if well dried, at length becomes a kind of gum, or rather, a hardened mucilage.
Lymph, transparent fluid.
Lymph, transparent fluid.
What is Gum Arabic?
The juice of a small tree of the Acacia tribe, growing in Egypt, Arabia Petræa, Palestine, and in different parts of America.
Are there other plants or trees which produce Gum, besides those already mentioned?
A great number, though not all commonly in use. The leaves of rhubarb, the common plum, and even the sloe and the laurel, produce a clear, tasteless gum; there are also a number of different gums, brought from foreign countries, of great use in medicine and the arts. Most of the Acacias produce gums, though the quality of all is not equally good.
What is Rhubarb?
A valuable root growing in China, Turkey, and Russian Tartary. Quantities of it are imported from other parts of the world: that from Turkey is esteemed the best. Rhubarb is also cultivated in our gardens, and the stalks of the leaves are often used in tarts; but the root, from the difference of climate, does not possess any medicinal virtue.
When were Spectacles invented, and who was their inventor?
It is supposed that they were first known about the thirteenth century, and invented by a monk of Pisa, in Italy, namedAlexander de Spina. Spectacles are composed of two circular pieces of glass set in a frame.
What are these glasses called?
Lenses. They are either convex or concave, according to the kind of sight requiring them. Old people, and those who can only see things at a distance, from the flatness of the eye, which prevents the rays of light converging so as to meet in the centre, require convex lenses. People who can only distinguish objects when viewed closely, from the eye being too convex, require concave lenses to counteract it by spreading the rays, and thus rendering vision distinct.
Convex, rising outwardly in a circular form; opposite to concave.Concave, hollow; round, but hollow, as the inner curve of an arch, &c.Converging, tending to one point from different parts.Vision, the faculty of seeing.
Convex, rising outwardly in a circular form; opposite to concave.
Concave, hollow; round, but hollow, as the inner curve of an arch, &c.
Converging, tending to one point from different parts.
Vision, the faculty of seeing.
What is the Mariner's Compass?
A most useful and important instrument, by the aid of which the navigator guides his ship on the sea, and steers his way to the place of his destination. The inventor of the Mariner's Compass is not known, nor the exact time of its introduction; it was employed in Europe in navigation about the middle of the thirteenth century, and has been in use more than five hundred years. The Chinese are said to have been acquainted with it much earlier, but no reliance can be placed on their dates. The power of the loadstone to attract iron was known to the ancient Egyptians, but it was not applied to any practical purpose.
Navigator, one who guides a ship.Steer, to direct or guide a vessel in its course.Destination, the place to which a person is bound.Practical, capable of practice, not merely speculative.
Navigator, one who guides a ship.
Steer, to direct or guide a vessel in its course.
Destination, the place to which a person is bound.
Practical, capable of practice, not merely speculative.
What is the Loadstone?
An ore of iron which possesses the peculiar property of attracting iron, namely, of drawing it in contact with its own mass, and holding it firmly attached by its own power of attraction. A piece of loadstone drawn several times along a needle,or a small piece of iron, converts it into an artificial magnet; if this magnetized needle is carefully balanced, it will turn round of itself, till its end points towards the North. The magnetized needle also possesses the power of attracting iron, and of communicating this power to another piece of iron or steel, similar to that of the loadstone itself.
Contact, touch.Magnetized, rendered magnetic.
Contact, touch.
Magnetized, rendered magnetic.
Describe the Mariner's Compass.
The Mariner's Compass consists of a circular box, enclosing a magnetized bar of steel, called theneedle, carefully balanced on an upright steel pivot, and having that end which points to the North shaped like the head of an arrow; attached to this needle, and turning with it, is a card on which are printed the divisions of North, South. East, and West; called the points of the compass. By simply looking at the position of the needle, the mariner can see the direction in which his vessel is sailing, and regulate his helm accordingly.
Helm, the instrument by which a ship is steered, consisting of a rudder and tiller.
Helm, the instrument by which a ship is steered, consisting of a rudder and tiller.
What is a Barometer?
An instrument for measuring the weight of the atmosphere, which enables us to determine the changes of the weather, the height of mountains, &c. It consists of a glass tube hermetically sealed at one end, filled with mercury, and inverted in a basin of mercury; according to the weight of the atmosphere, this mercury rises or falls.
How is the Hermetic seal formed?
By heating the edges of a vessel, till they are just ready to melt, and then twisting them closely together with hot pincers, so that the air may be totally excluded. The word is taken from Hermes, the Greek name for Mercury, the heathen god of arts and learning, and the supposed inventor of chemistry,[9]which is sometimes called the hermetical art; or perhaps from Hermes, an ancient king of Egypt, who was either its inventor, or excelled in it.
[9]See Chapter XVIII., articleChemistry.
[9]See Chapter XVIII., articleChemistry.
What is Mercury?
Quicksilver, or mercury, is a white fluid metal, the heaviest except platina and gold; it readily combines with nearly all other metals, and is used in the manufacture of looking-glasses, barometers, thermometers, &c.; in some of the arts, and in the preparation of several powerful medicines. It is found in California, Hungary, Sweden, Spain, China, and Peru. The quicksilver mine of Guança Velica, in Peru, is one hundred and seventy fathoms in circumference, and four hundred and eighty deep. In this profound abyss are seen streets, squares, and a chapel, where religious worship is performed. The quicksilver mines of Idria, a town of Lower Austria, have continually been wrought for more than 300 years. The vapor which is continually arising from the mercury is very hurtful to the miners, who seldom survive many years.
Abyss, a gulf, a depth without bottom.
Abyss, a gulf, a depth without bottom.
In what state is Mercury usually found?
Either native, or in the form of ore; it is often found mixed with silver, but more frequently with sulphur in the form of sulphuret, which is decomposed by distillation. Running mercury is found in globules, in America, and is collected from the clefts of the rocks. Mercury has the appearance of melted silver; it is neither ductile nor malleable in this state; it is a substance so volatile, when heated, that it may be evaporated like water; it is always seen in a fluid state, even in temperate climates, as a very small portion of heat is sufficient to preserve its fluidity. It is used to separate gold and silver from the foreign matter found with those metals. Calomel, a valuable medicine, and vermilion, a color, are both preparations of mercury.
Globules, small particles of matter having the form of a ball or sphere.
Globules, small particles of matter having the form of a ball or sphere.
What is a Thermometer?
An instrument for measuring temperature. It consists of a fine glass tube, terminated at one end in a bulb, usually filled with mercury, which expands or contracts according to the degree of heat or cold. On the scale of the Fahrenheit thermometer, the freezing point of water is marked 32° and the boiling point at 212°. In both the Centigrade and the Reaumur scales the freezing point is at 0, and the boiling point at 100° in the Centigrade and at 80° in Reaumur's. The invention of this instrument dates from about the close of the sixteenth century; but it is not known by whom it was first brought into use.
Terminated, finished, ended.
Terminated, finished, ended.
When and by whom were Watches and Clocks invented?
Watches were invented about the year 1500, but who was the inventor is disputed. They were, however, of little value as time-keepers, before the application of the spiral spring as a regulator to the balance; the glory of this excellent invention lies between Dr. Hooke and M. Huygens; the English ascribing it to the former, the Dutch, French, &c., to the latter. Some assert that pocket-watches were first made about 1477, at Nuremberg, in Germany. The most ancient clock of which we possess any certain account, was made in 1634 by Henry de Wycke, a German artist; it was erected in a tower of the palace of Charles V., king of France. The pendulum was applied by Huygens, in 1656.
What is a Pendulum?
A weight so suspended from a fixed point that it may easily swing backward and forward; its oscillations are always performed in equal times, provided the length of the pendulum and the gravity remain the same. It is said that the idea of employing the pendulum for the measurement of time, was first conceived by Galileo, while a young man, upon his observing attentively the regular oscillations of a lamp suspended from the roof of a church in Pisa. It was not, however, till the time of Huygens that a method was devised of continuing its motions, and registering the number of its oscillations.
Oscillation, a swinging backward and forward.Gravity, the tendency of a body toward the centre of the earth.Registering, recording.
Oscillation, a swinging backward and forward.
Gravity, the tendency of a body toward the centre of the earth.
Registering, recording.
CHARCOAL BURNING.CHARCOAL BURNING.
GOLD MINERS WASHING ORE.GOLD MINERS WASHING ORE.
To whom is the invention of Gunpowder ascribed?
Most authors suppose it was invented by Bartholdus Schwartz, a monk of Goslar, a town of Brunswick, in Germany, about the year 1320; it appears, however, that it was known much earlier in many parts of the world, and that the famous Roger Bacon, who died in 1292, knew its properties; but it is not certain that he was acquainted with its application to fire-arms.
Who was Roger Bacon?
A learned Franciscan, born at Ilchester, England, in 1214. He studied at Oxford, and afterwards became professor at that great University. He was familiar with every branch of human knowledge, but was especially distinguished for his extraordinary proficiency in the natural sciences. To him we owe the invention of the telescope; that of gunpowder is ascribed to him, as stated above, although we have no evidence to show whether he discovered its ingredients himself, or whether he derived the knowledge from some ancient manuscripts. Bacon suffered some from the ignorance of the age in which he lived, many of his experiments being looked upon as magic. He died at Oxford in the year 1294.
What is understood by Magic?
Magic is a term used to signify an unlawful and wicked kind of science, depending, as was pretended, on the assistance of superhuman beings and of departed souls. The term was anciently applied to all kinds of learning, and in particular to the science of the Magi or Wise Men of Persia, from whom it was called magic.Naturalmagic is no more than the application of natural active causes to passive things or subjects, to produce effects apparently supernatural.
Supernatural, beyond the powers of nature; miraculous.
Supernatural, beyond the powers of nature; miraculous.
Of what is Gunpowder composed?
Of saltpetre,[10]sulphur, and charcoal, mixed together and powdered; its explosive force when fired, is owing to the instantaneous and abundant liberation of gaseous matter by the intense heat resulting from the action of the combustibles upon the saltpetre. It is not known by whom it was first applied to the purposes of war, but it is certain that it was used early in the fourteenth century. Cannons were used at the battle of Cressy, in 1346; small guns, or muskets, were introduced into the Spanish army in 1521.
[10]SeeChapter XIII.
[10]SeeChapter XIII.
Explosive, bursting out with violence and noise.Liberation, a setting at liberty.
Explosive, bursting out with violence and noise.
Liberation, a setting at liberty.
Is not Gunpowder highly combustible?
So combustible is gunpowder, that a single spark of fire, lighting upon any of it, will cause it to explode with immense force; and instances have occurred, when any store or magazine of it has taken fire, that have been attended with the most fatal effects. It is useful to the miner and engineer as a ready means of overcoming the obstacles which are presented in their search for mineral treasures, and in procuring materials for building. From many passages in the ancient authors, there is reason to suppose that gunpowder, or a composition extremely like it, was known to them; but it does not appear to have been in general use, and the invention of fire-arms is comparatively modern. Dynamite, a recent invention, has a still greater explosive force than gunpowder.
Engineer, one who works or directs an engine.Obstacles, hinderances, obstructions.
Engineer, one who works or directs an engine.
Obstacles, hinderances, obstructions.
What is Saltpetre?
A bitter kind of salt, called by the ancients nitre, but more commonly among us saltpetre. It is composed of nitric acid and potassa.[11]It is found in earthy substances; sometimes native or pure, in the form of a shapeless salt. Vast quantitiesare found in several of the marly earths of the East Indies, China, Persia, and also in South America. In India it is found naturally crystallized, and forming thin crusts upon the surface of the earth. It is especially abundant in the United States, being found in immense quantities in the limestone caves in the south-western States.
[11]SeePotash, Chapter VII., articleGlass.
[11]SeePotash, Chapter VII., articleGlass.
What do you mean byMarly?
Consisting of marl, a kind of earth composed of different proportions of clay and carbonate of lime; it is much used for manure. There are several different-colored marls, each possessing different qualities. The most common are the red and the white, though there are grey, brown, blue, and yellow colored marls.
What is a Telescope?
An optical instrument, which serves for discovering and viewing distant objects, either directly by glasses, or by reflection. The invention of the telescope is one of the noblest and most useful of which modern ages can boast, since by means of this instrument the wonderful motions of the planets and fixed stars, and all the heavenly bodies, are revealed to us. The honor of the invention is much disputed; it is certain, however, that the celebrated Galileo was the first who improved the telescope so as to answer astronomical purposes. The name is formed from two Greek words, one signifyingfar, the otherto observe.
Optical, relating to Optics, the science of vision.Astronomical, relating to Astronomy.
Optical, relating to Optics, the science of vision.
Astronomical, relating to Astronomy.
Who was Galileo?
A most eminent astronomer and mathematician, born at Florence, in Italy. His inventions and discoveries in Astronomy, Geometry, and Mechanics, contributed much to the advancement of those sciences. He died in 1642.
Astronomer, one versed in Astronomy.Mathematician, one versed in Mathematics; a science which treats of magnitude and number.
Astronomer, one versed in Astronomy.
Mathematician, one versed in Mathematics; a science which treats of magnitude and number.
What is Astronomy?[12]
That science which teaches the knowledge of the heavenly bodies, with the nature and causes of their various phenomena.
[12]SeeChapter XVIII.
[12]SeeChapter XVIII.
What is Geometry?
An ancient, perfect, and beautiful science, which treats of the relations and properties of lines, surfaces, and solids.
What is meant by Mechanics?
The science which investigates the laws of forces and powers, and their action on bodies, either directly or by machinery. When the termmechanicis applied to aperson, it means one skilled in mechanics, accustomed to manual labor.
Investigate, to search, to inquire into.Manual, performed by the hand.
Investigate, to search, to inquire into.
Manual, performed by the hand.
What is a Microscope?
An optical instrument, by means of which very minute objects are represented exceedingly large, and viewed very distinctly according to the laws of refraction or reflection. Nothing certain is known respecting the inventor of microscopes, or the exact time of their invention, but that they were first used in Germany, about 1621.
Minute, small, diminutive.Refraction, a change in the direction of a ray of light, when it passes through transparent substances of different densities.Reflection, a turning back of a ray of light after striking upon any surface.
Minute, small, diminutive.
Refraction, a change in the direction of a ray of light, when it passes through transparent substances of different densities.
Reflection, a turning back of a ray of light after striking upon any surface.
What is the Steam Engine?
A machine that derives its moving power from the force of the steam produced from boiling water, which is very great, especially when, as in the steam engine, it is confined within a limited compass: this useful machine is one of the most valuable presents that the arts of life have received from the philosopher, and is of the greatest importance in working mines; supplying cities with water; in working metals; in many mechanical arts; and in navigation. By the aid of steam, vesselsare propelled with greater swiftness than those which are wholly dependent on the winds and tides; and thus trade is facilitated, and we are enabled to communicate with distant lands in a much shorter space of time than was formerly consumed. On land, railroads are constructed, on which steam carriages run with astonishing rapidity, so that a journey which by coach and horses formerly required two or more days, may now be performed in four or five hours.
Mechanical, belonging to Mechanics.
Mechanical, belonging to Mechanics.
To whom are we indebted for its invention?
Its invention is by most writers ascribed to the Marquis of Worcester, an Englishman, about 1663; but it does not appear that the inventor could ever interest the public in favor of this, or his other discoveries. The steam engine of Captain Savery, also an Englishman, is the first of which any definite description has been preserved. It was invented in 1698. Since that period it has been successively improved by various persons, but it is to Mr. Watt and Mr. Boulton, of England, that it is indebted for much of its present state of perfection.
By whom was the Steam Engine first applied to the purposes of Navigation?
By John Fitch, of Pennsylvania. From papers in the historical collections of Pennsylvania, it appears that the first successful experiments were made at Philadelphia, in 1785, three years before the attempts at Falkirk, and on the Clyde, in Scotland. The boat made several trips on the Delaware and Schuylkill rivers, but owing to repeated accidents to her machinery, and the want of funds and competent mechanics for the necessary repairs, she was abandoned. In 1807, Robert Fulton, also of Pennsylvania, made his first experimental trip on the Hudson River, with complete success. To this distinguished and ingenious American justly belongs the honor of having brought navigation by steam to a state of perfection. In 1819, the first steamship crossed the Atlantic from Savannahto Liverpool; and in 1838, a regular communication by steamship was established between Great Britain and the United States. Since that period, ocean navigation by steam-vessels has made rapid progress, and, at the present time, numbers of steamers connect our various seaports with those of other nations, and with each other.
What is the Electro-Magnetic Telegraph?
An instrument, or apparatus, by means of which intelligence is conveyed to any distance with the velocity of lightning. The electric fluid, when an excess has accumulated in one place, always seeks to transfer itself to another, until an equilibrium of its distribution is fully restored. Consequently, when two places are connected by means of a good conductor of electricity, as, for instance, the telegraphic wire; the fluid generated by a galvanic battery, if the communication be rendered complete, instantaneously traverses the whole extent of the wire, and charges, at the distant station, an electro-magnet; this attracts one end of a lever, and draws it downward, while the other extremity is thrown up, and, by means of a style, marks a slip of paper, which is steadily wound off from a roller by the aid of clock-work. If the communication is immediately broken, only one wave of electricity passes over, and adotis made upon the paper; if kept up, alineis marked. These dots and lines are made to represent the letters of the alphabet, so that an operator employed for the purpose can easily read the message which is transmitted.—The Electro-Magnetic Telegraph was first introduced upon a line between Baltimore and Washington, by Professor Morse, in 1844; at the present time, it is in successful operation between nearly all the important cities and towns of the United States and of Europe.
AnElectro-Magnetis a piece of soft iron, rendered temporarily magnetic by being placed within a coil of wire through which a current of electricity is passing.
AnElectro-Magnetis a piece of soft iron, rendered temporarily magnetic by being placed within a coil of wire through which a current of electricity is passing.
Of what is Soap composed?
Of soda or potash, and various oily substances; it is so useful for domestic and other purposes, that it may be regarded as one of the necessaries of life; immense quantities of it are consumed in all civilized countries. Soft soap is generally made of a lye of wood-ashes and quicklime, boiled up with tallow or oil; common household soap of soda and tallow, or of potash and tallow; when potash is used, a large portion of common salt, which contains soda, is added to harden it. The finest white soaps are made of olive oil and a lye consisting of soda and quicklime; perfumes are sometimes added, or various coloring matters stirred in to give the soap a variegated appearance. The ancient Greeks and Hebrews appear to have been acquainted with the art of making soap, or a composition very similar to it; and also the ancient Gauls and Germans. A soap-boiler's shop, with soap in it, was found in the city of Pompeii, in Italy, which was overwhelmed by an eruption of Mount Vesuvius, A.D. 79.
What is Soda?
Soda, or barilla, is obtained from the ashes of marine plants, and by the decomposition of common salt; its great depository is the ocean, soda being the basis of salt. The marine plants from which the soda is obtained, are endowed with the property of decomposing the sea-salt which they imbibe, and of absorbing the soda which it contains. It is found native in Egypt, and is there callednatron; a name similar to that which it bore among the Jews and Greeks.
Depository, store-house, place where anything is lodged.Imbibe, to drink in, to absorb.
Depository, store-house, place where anything is lodged.
Imbibe, to drink in, to absorb.
Of what are Candles made?
Of Tallow, which means animal fat melted and clarified, that is, cleansed or purified from filth. Tallow is procured from many animals, but the most esteemed, and the most used, is that made from oxen, sheep, swine, goats, deer, bears, &c.; some of which tallows or fats are used in medicine, some in making soap, and dressing leather; others in the manufacture of candles, &c. For the last-mentioned article, that of sheep and oxen is most used; candles of a better sort are likewise made of wax and spermaceti. Candles are kept burning by means of a wick of cotton or rush, placed in the centre of the tallow, which is moulded into a cylindrical form.
Cylindrical, having the form of a cylinder.
Cylindrical, having the form of a cylinder.
Is there not a tree which yields a vegetable Tallow?
Yes; China possesses a tree producing a substance like our tallow, of which the Chinese make their candles; this tallow is extracted from the stone of the fruit, the tallow being a white pulp which surrounds it. In America, likewise, there is a shrub, a native of the temperate parts, especially towards the sea-side, the seeds of which contain a waxy substance used for the same purpose, and which is extracted by boiling; this shrub is a species of myrtle, and does not attain to any great size.
Extracted, drawn from.
Extracted, drawn from.
What is Spermaceti?
A whitish, flaky, unctuous substance, prepared from an oil of the same name, drawn from a particular kind of whale, distinguished from the common whale by having teeth, and a hunch on its back.
Flaky, having the nature of flakes.
Flaky, having the nature of flakes.
What is Wax?
A soft, yellow, concrete matter, collected from vegetables bythe bee, of which this industrious and useful insect constructs its cell. Wax forms a considerable article of trade; it is of two kinds, the yellow and the white; the yellow is the native wax as it is taken from the hive, and the white is the same washed, purified, and exposed to the air.
Concrete, grown together, solid.
Concrete, grown together, solid.
What Tree produces the beautiful and well-known wood so much used in making the various articles of household furniture?
The Mahogany Tree, growing in America, and the East and West Indies; it frequently grows in the crevices of rocks, and other places of the same description. This wood was not used for making furniture till near the end of the seventeenth century. A London physician had a brother, the captain of a West India ship, who, on his return to England, having on board several logs of mahogany for the purpose of ballast, made him a present of the wood, he being engaged in a building project; his carpenter, however, threw it aside, observing that it was too hard to be wrought. Some time after, the lady of the physician being in want of a box to hold candles, the cabinet-maker was directed to make it of this wood; he also made the same objection, and declared that it spoiled his tools. Being urged, however, to make another trial, he at length succeeded; when the box was polished, the beautiful color of the wood was so novel, that it became an object of great curiosity. Before this time, mahogany had been used partially in the West Indies for ship-building, but this new discovery of its beauty soon brought it into general use for making furniture.
Crevice, a rent, a crack.Ballast, the heavy matter placed in the hold of a vessel to keep it steady.
Crevice, a rent, a crack.
Ballast, the heavy matter placed in the hold of a vessel to keep it steady.
What is India Rubber or Caoutchouc?
An elastic, resinous substance, produced from a tree, growing abundantly at Cayenne, Quito, and other parts of South America; and also in some parts of the Indies. The tree whichproduces it is large, straight, and about sixty feet high. There is, however, a small species found in Sumatra and Java, and some of the neighboring islands.
How is the Caoutchouc obtained from the Tree?
By making incisions in the trunk of the tree, from which the fluid resin issues in great abundance, appearing of a milky whiteness at first, but gradually becoming of a dark reddish color, soft and elastic to the touch.
To what use is this substance put?
The Indians make of it boots, shoes, bottles, flambeaux, and a species of cloth. Amongst us it is combined with sulphur, forming the vulcanized rubber of commerce, which is used for many purposes. A greater proportion of sulphur, produces vulcanite, a hard black substance, resembling jet.
Flambeaux, torches burnt to give light.
Flambeaux, torches burnt to give light.
What is Sponge?
A marine substance, found adhering to rocks and shells under the sea-water, or on the sides of rocks near the shore. Sponge was formerly imagined by some naturalists to be a vegetable production; by others, a mineral, or a collection of sea-mud, but it has since been discovered to be the fabric and habitation of a species of worm, or polypus.
What do you mean by Polypus?
A species of animals called Zoophytes, by which are meant beings having such an admixture of the characteristics of both plants and animals, as to render it difficult to decide to which division they properly belong. They are animal in substance, possessed indeed of a stomach, but without the other animal characteristics of blood-vessels, bones, or organs of sense; these creatures live chiefly in water, and are mostly incapable of motion: they increase by buds or excrescences from the parent zoophyte, and if cut off will grow again and multiply; each part becoming a perfect animal. Myriads of the different species of zoophytes reside in small cells of coral, sponge, &c., or in formslike plants, and multiply in such numbers as to create rocks and whole islands in many seas, by their untiring industry. Polypus signifies having many feet, or roots; it is derived from the Greek.
Myriads, countless numbers.
Myriads, countless numbers.
Whence are the best and greatest number of Sponges brought?
From the Mediterranean, especially from Nicaria, an island near the coast of Asia: the collection of sponges forms, in some of these islands, the principal support of their inhabitants. They are procured by diving under water, an exercise in which both men, women, and children are skilled from their earliest years. The fine, small sponges are esteemed the best, and usually come from Constantinople; the larger and coarser sorts are brought from Tunis and Algiers, on the coast of Africa. Sponge is very useful in the arts, as well as for domestic purposes.
What is Coral?
A substance which, like sponge, was considered as a vegetable production, until about the year 1720, when a French gentleman of Marseilles commenced (and continued for thirty years,) a series of observations, and ascertained that the coral was a living animal of the Polypus tribe. The general name of zoophytes, or plant animals, has since been applied to them. These animals are furnished with minute glands, secreting a milky juice; this juice, when exuded from the animal, becomes fixed and hard.
Series, a course or continued succession.Glands, vessels.Exuded, from exude, to flow out.
Series, a course or continued succession.
Glands, vessels.
Exuded, from exude, to flow out.
Is this substance considered by naturalists as the habitation of the Insect?
Not merely as the habitation, but as a part of the animal itself, in the same manner that the shell of a snail or an oyster is of those animals, and without which they cannot long exist.By means of this juice or secretion, the coral insects, at a vast but unknown depth below the surface of the sea, attach themselves to the points and ridges of rocks, which form the bottom of the ocean; upon which foundation the little architects labor, building up, by the aid of the above-mentioned secretion, pile upon pile of their rocky habitations, until at length the work rises above the sea, and is continued to such a height as to leave it almost dry, when the insects leave building on that part, and begin afresh in another direction under the water. Huge masses of rocky substances are thus raised by this wonderful little insect, capable of resisting the tremendous power of the ocean when agitated to the highest pitch by winds or tempests.
Architect, one who builds.
Architect, one who builds.
How do these Coral Rocks become Islands?
After the formation of this solid, rocky base, sea-shells, fragments of coral, and sea-sand, thrown up by each returning tide, are broken and mixed together by the action of the waves; these, in time, become a sort of stone, and thus raise the surface higher and higher; meanwhile, the ever-active surf continues to throw up the shells of marine animals and other substances, which fill up the crevices between the stones; the undisturbed sand on its surface offers to the seeds of trees and plants cast upon it by the waves, a soil upon which they rapidly grow and overshadow the dazzling whiteness of the new-formed land. Trunks of trees, washed into the sea by the rivers from other countries and islands, here find a resting-place, and with these come some small animals, chiefly of the lizard and insect tribe. Even before the trees form a wood, the sea-birds nestle among their branches, and the stray land-bird soon takes refuge in the bushes. At last, man arrives and builds his hut upon the fruitful soil formed by the corruption of the vegetation, and calls himself lord and master of this new creation.
Surf, the white spray or froth of the sea waves.
Surf, the white spray or froth of the sea waves.
Where is the Coral Insect found?
In nearly all great seas; but particularly in the Mediterranean, where it produces Corallines of the most beautiful forms and colors: it is in the Pacific Ocean, however, where these tiny workmen are effecting those mighty changes, which exceed the most wonderful works of man.
What is that part of the Pacific called, where the Coral Rocks are most abundant?
The Coral Sea, from the number of coral reefs and sunken islands, with which it abounds; it includes a region of many miles in extent, the whole of which is studded with numberless reefs, rocks, islands, and columns of coral, continually joining and advancing towards each other. All navigators who have visited these seas, state that no charts or maps are of any service after a few years, owing to the number of fresh rocks and reefs which are continually rising to the surface. The wonderful instinct of these animals leads them to continue working without ceasing, until their labors are finished, or their lives extinct.
Reef, a chain or line of rocks lying near the surface of the water.Extinct, at an end, dead.
Reef, a chain or line of rocks lying near the surface of the water.
Extinct, at an end, dead.
What are the names of the principal islands of Coral formation?
The New Hebrides, the Friendly Isles, the Navigator's Isles, the Society Islands, the Marquesas, the Gambier group, and others. These groups are separated from each other by channels or seas, wider than those which divide the individual islands which form the respective groups; but all these waters abound with shoals and minor islets, which point out the existence of a common base, and show that the work by which they will afterwards be united above the level of the sea is continually going forward.
Shoals, shallows; places where the water is of little depth.Minor, less, smaller than others.Existence, being.
Shoals, shallows; places where the water is of little depth.
Minor, less, smaller than others.
Existence, being.
What is a singular characteristic of the Coral Islands?
On all of them a plentiful supply of sweet and fresh watermay be obtained by digging three or four feet into the coral; and even within one yard of high-water mark such a supply is to be found. They are mostly covered with a deep rich soil, and well wooded with trees and evergreens of different kinds. These islands vary in extent, as well as in the degree of finish to which they have arrived; some of the largest being about 30 miles in diameter, and the smallest something less than a mile;—all of various shapes, and all formed of living coral.
Diameter, a straight line through the middle of a circle.
Diameter, a straight line through the middle of a circle.
Is Coral put to any use by man?
White Coral, which is nowhere so abundant as about the shores of Ceylon, and others of the neighboring Indian coasts, is employed as lime by the inhabitants of that part of the world, for building houses, &c., by burning it after the manner of our lime. This coral lies in vast banks, which are uncovered at low water. Coral, particularly the beautiful red sort, is likewise made into various ornaments, as necklaces, &c.
Of what is our Lime composed?
Of a useful earth, which absorbs moisture and carbonic acid, and exists as limestone, or in marble and chalk, which, when burnt, become lime: in its native state it is called carbonate of lime, and is burnt to disengage the carbonic acid; when made into a paste, with one part water and three parts lime,[13]and mixed with some other mineral or metallic substances, it forms plastic cements and mortars; and afterwards, imbibing carbonic acid from the atmosphere, it becomes again carbonate of lime, as hard as at first; and hence its use in building.
[13]See Chapter XVI., articleLime.
[13]See Chapter XVI., articleLime.
Plastic, yielding, capable of being spread out or moulded.
Plastic, yielding, capable of being spread out or moulded.
What do you mean by Carbon?
A simple substance, whose most common form is purified charcoal: it is, in fact, the base of charcoal, divested of all impurities; combined with oxygen, it formscarbonic acidgas,formerly called fixed air. It is diffused through all animal and vegetable bodies; and may be obtained by exposing them to a red heat. In its pure, crystallized state, it constitutes the diamond, and as graphite, is used in making the so-called lead-pencils.[14]
[14]See Chapter XIV., articleDiamond.
[14]See Chapter XIV., articleDiamond.
What is Oxygen?
Air, mentioned in the first chapter of this work as the gaseous substance which composes the atmosphere, is formed by a mixture of two distinct elements, one called Nitrogen, or Azote, the other Oxygen. Oxygen is, therefore, an element or simple substance diffused generally through nature, and its different combinations are essential to animal life and combustion. It is, in fact, the most active agent in nature, and the principle of acidity and combustion. So wholesome and necessary is oxygen to life, that it is often called vital air.